sorry, but you cant change the size of the icons.but, you may want to try to use go launcher because it has an option to change the size of the icons of the apps to small or big or custom. but, i dont feel too much different from the default size of the icons from twlauncher(default launcher for stock rom)

The code is for a file in system folder called build.prop .If you dont know how to use the code, then just flash the above files using cwm and it'll do this hack for you.But, if you want to use the code to do this hack,then u need to1. Open Root Explorer.2. Go to system folder and open build.prop file in text editor[in your phone]3. add the above codes at the end of the all the codes in build.prop file.It's just two different ways to do the same hack.